Abstract: For wideband digital array radar, it is necessary for the conventional digital beamforming methods to obtain the direction of arrivial(DOA) of the signal and interference precisely. Little estimating error causes large focusing error, which may also affect the feasibility of the whole system. To solve the problem mentioned above, a new wideband adaptive digital beam forming algorithm based on improved Bayesian focusing method is proposed. It is assumed that the probability functions of DOAs of the interested signal and interferences are uniform and obey the Gaussian distribution respectively. Then the adaptive weight vector and focusing matrix are calculated. The reason why the conventional method cannot be used in different beams is analyzed in details. The procedure of the adaptive monopusle method using the proposed algorithm is also given in this paper. Simulation results verify the correctness and effectiveness of the proposed algorithm.